Bovine pancreatic DNase I binds very tightly to DNA fragments and may be mistaken for putative endogenous nuclear proteins covalently bound to DNA.
Using published methods for the isolation of nuclear proteins tightly bound to DNA, and resistant to removal by SDS or 16-BAC detergent and urea, several new protein bands in the region of 55 kd and 62 kd on SDS gel and 43 kd and 70 kd on 16--BAC gel electrophoresis were identified in extracts of avian erythroid nuclei. These bands were radiolabelled by subjecting the DNA--protein complexes to nick--translation in the presence of [32P]--dCTP, followed by prolonged digestion with excess bovine DNase I. Amino acid sequence analysis shows that these bands contain DNase I. These results indicate that DNase I can form stable complexes with DNA, and suggest that DNase I--DNA complexes may be mistakenly identified as nuclear proteins covalently bound to DNA.
Brotherton
T W
TW
Department of Internal Medicine, University of Iowa, Iowa City.
Zenk
D W
DW
D000595:Amino Acid Sequence; D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism; D002645:Chickens; D004247:DNA / Q000097:blood / Q000302:isolation & purification / Q000378:metabolism*; D003850:Deoxyribonuclease I / Q000302:isolation & purification / Q000378:metabolism*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009687:Nuclear Proteins / Q000302:isolation & purification / Q000378:metabolism*; D010179:Pancreas / Q000201:enzymology*; D011485:Protein Binding; D014176:Protein Biosynthesis; D012156:Reticulocytes / Q000378:metabolism
D009687:Nuclear Proteins; D004247:DNA; D003850:Deoxyribonuclease I